Trammel-head



(No Model.)

R. G. HAUSDORFER.

TRAMMEL HEAD.

No. 447,642. Patented Mar. 3,1891.

WITNESSES w uz eczj lb INVENTOH ATTORNEYS I EH5 um, vmrro-umm, WASNINGTONrrnn STATES rrrcn.

I ATENT TRAMMEL-HEAD.

SPECIFICATION forming part of Letters Patent No. 447,642, dated March 3,1891.

Application filed September 18, 1890. Serial No. 365,344. (No model.)

To aZZ whom, it may concern.-

Be it known that I, REINHOLD G. HAUS DoRFER, of Zanesville, in thecounty of Muskingum and State of Ohio, have invented a new and usefulImprovement in Trammel- Heads, of which the following is a full, clear,and exact description.

This invention relates to an improvement in tramrnel-heads that hold thepoints for a beam-compass used to project large curves and circles, andhas for its objects to provide a device of the genus specified whichwill be neat in appearance, easy to construct, and that will affordmeans to secure the points of the beam-compass in a reliable manner uponthe elongated bar or beam of the instrument and adjust them with greataccuracy.

To these end my. invention consists in the construction of parts andtheir combination, as is hereinafter described and claimed.

Reference is to be had to the accompanying drawings, forming a part ofthis specification, in which similar letters of reference indicatecorresponding parts in all the figures.

Figure 1 is a side elevation of the device on the end portion of. acompass-beam broken. Fig. 2 is a transverse section of the trammelheadand its point, taken on the broken line 2 2 in Fig. 1,the beambeing alsoshown. Fig. 3 is a longitudinal section of the trammelhead on the line 33 of Fig. 2, and Fig. 4 is a detached View of one of the parts of thehead.

The head-frame A is made of any suitable metal, and consists of twoparallel walls a a, which are retained properly spaced apart by the hubb at the lower end of the walls, and which have their opposite edgesoutwardly curved an equal degree to the points a, where outward swellsare produced on the edges, whereby a graceful design is secured for theside walls a a and asuitably-increased width afforded to them near theirupper edges, that are integrally joined by the formation of the similarbosses (Z between the side walls near their side edges, The bosses (Zare verticallyand axially perforated and internally threaded for theintroduction of the similar thumbscrews 6, which are of sufficientlengthto permit them to have a proper range of vertical adjustment.

The compass-beam B is preferably made of hard wood (but any material mayhe used that is suitable) and is rectangular in crossseotion, as usual,having a length proportionate to the diameter of circles to beinscribed. The sides and edges from their parallelism, respectivelyconsidered, permitting one or a pair of trammel-heads of improved formto be moved to any. desired position on the beam.

The head-frame A is given such a proportionate width between itsparallel walls a that a shoe C (shown in perspective in Fig. 4) may beslid between said walls a a and neatly fill the intervening space.

As will be seen, the shoe 0 has two walls g, that are held spaced apartby the integral base-wall g, the vertical channel afforded be- I tweenthese parallel Walls 9 being so proportioned that the beam B Will neatlyfit and slide therein. Sufficient length is given to the base-wall g ofthe shoe 0 to provide an elongated bearing-face between the base of theshoe and adjacent edge of the beam B. The edges 9 of the side walls gare curved upwardly and inwardly from the ends of the base-wall g andterminate in cars it at their upper portions, which project above thebeam B when the parts are assembled, said ears being rounded on theiredges to conform in shape to the upwardly-curved upper edges of theframe sides a.

An elongated clamping-plate D is provided, which is made of such a widthas will permit it to slide between the walls of the shoe 0, its lengthbeing preferably made greater than that of the base-wall g of the shoe.At the longitudinal center of the clamping-plate D an ear 2' is producedon the upper side of said plate, having a transverse aperture 1'' formedin it, which is in the form of a short vertically-extending slot.

There are aligning perforations made in the cars 7L of the shoe 0 andalso in the side Walls a of the trammel-block frame A at suchcorresponding points as will allow the curved upper edges of these carsand the side walls a to conform when a rivet or fulcrum-pin m isinserted through the registering perforations.

When the parts are assembled, the clamping-plate D is placed in positionbetween the walls g of the shoe 0 and the fulcrum-pin m inserted throughits vertically-elongated slot 1' as it passes through the otherperforations of the frame A and shoe the pin m being then secured inplace by riveting its ends, or other means.

5 Any ordinary trammel head or a fixed trammel-point may be used inconjunction with the improved trammel-head, which has a steel taperedpoint A secured in the huh I), axially coincident with it, the plane ofthe axes of the point A and thumb-screws e being parallel.

By an adjustment of the thumb-screws c the clamping-plate I) may beloosened, so that the improved trammeLhead may he slid to any desiredpoint on the beam 13 and be secured thereon.

In use the trammel-heads are adjusted to the length of the radiusrequired, or as near as is convenient, by sliding one head and affixingthe thumb-screws of both heads. Should a slight correction be necessaryto lengthen or shorten the distance between the trammelpoints at theirfine terminal ends, this can be effected by the manipulation of thethumbscrews (2, as by slackening one screw and tightening the otherscrew of the pair on a frame A said frame will be rocked slightly andthe trammel-point moved correspondingly, so that a fine adj ustment ofthe points is 50 thus afforded, which, when attained, may be made secureby a tightening of the screws 6, so as to firmly clamp the beam ll.

Having thus described my invention, I claim as new and desire to secureby Letters Patent 1. The combination, with a head-frame and atrammel-point thereon, of a shoe pivoted within the frame, aclamping-plate, and-two thumb-screws which engage this plate,substantially as set forth.

2. The combination, with a head-frame and a trammel-point thereon, of ashoe within the frame, a clamping-plate, two thumb-screws mounted in theframe and engaging the plate, and a fulcrum-pin uniting the frame andshoe and on which the plate is loosely mounted, substantially asspecified.

3. The combination, with abeam, of a headframe, a trammel-point, a shoepivoted to swing in the frame, a clamping-plate adapted to rock and movevertically in the shoe, and two set-screws which are adjustable in theframe and bear on the clamping-plate near its ends, substantially as setforth.

4:. The combination, with a compass-beam which is rectangular incross-section, of a headframe having spaced parallel walls wh ich arejoined below by a hub, a tapered point in the hub, a shoe which embracesthe beam and slides between the walls of the headframe, the frame andshoe being perforated transversely near their upper edges and 1011-gitudinal centers, two vertical thumb-screws inserted in threadedperforations of integral bosses on the head-frame which are at an equaldistance from the perforations, a clamping-plate located in the shoe andtransversely slotted through a longitudinally central ear, and afulcrum-pin which retains the frame, shoe, and clamping-plate in looseadjustment, substantially as set forth.

REINIIOLD G. llAUSDfiRl' l lR.

\Vitnesses:

JOSEPH ScHoLL, D. 1%. LINN.

